Now I want to add another Firewall but for a specific vlan [192.168.40.] and route their internet traffic through their firewall[192.168.40.1], but I am a litte lost.What static route can I make for them ?

If you had the right hardware (like the ERS 8800) and software releases (7.0 and above) you could use VRFs. It allows for separate routing instances to exist on the same switch. So each can have their own default route. It allows for inter-VRF routing as well.